首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1057433篇
  免费   79630篇
  国内免费   2787篇
耳鼻咽喉   13731篇
儿科学   35804篇
妇产科学   29318篇
基础医学   153090篇
口腔科学   28857篇
临床医学   96831篇
内科学   205922篇
皮肤病学   23623篇
神经病学   85009篇
特种医学   40431篇
外国民族医学   309篇
外科学   160082篇
综合类   24350篇
一般理论   436篇
预防医学   82135篇
眼科学   23787篇
药学   76092篇
  3篇
中国医学   2094篇
肿瘤学   57946篇
  2021年   8652篇
  2019年   8946篇
  2018年   12541篇
  2017年   9674篇
  2016年   10894篇
  2015年   12325篇
  2014年   16865篇
  2013年   25112篇
  2012年   33751篇
  2011年   35796篇
  2010年   21157篇
  2009年   19920篇
  2008年   32791篇
  2007年   34579篇
  2006年   34857篇
  2005年   33397篇
  2004年   32257篇
  2003年   30969篇
  2002年   29685篇
  2001年   47425篇
  2000年   48420篇
  1999年   40746篇
  1998年   11780篇
  1997年   10573篇
  1996年   10554篇
  1995年   10113篇
  1994年   9385篇
  1993年   8758篇
  1992年   32521篇
  1991年   31681篇
  1990年   31186篇
  1989年   30052篇
  1988年   27343篇
  1987年   27477篇
  1986年   25560篇
  1985年   24727篇
  1984年   18535篇
  1983年   15636篇
  1982年   9405篇
  1979年   16939篇
  1978年   12283篇
  1977年   10392篇
  1976年   9811篇
  1975年   10224篇
  1974年   12355篇
  1973年   11876篇
  1972年   10911篇
  1971年   10139篇
  1970年   9413篇
  1969年   8751篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
991.
The Budd-Chiari syndrome (BCS) is caused by hepatic venous outflow obstruction, which often leads to death as a result of portal hypertension and liver failure. Therapeutic approaches vary widely from conventional medical therapy to liver transplantation. If and when a patient suffering with BCS needs surgery remains a matter of contention. However, it is well accepted that portacaval shunt surgery and orthotopic liver transplantation represent efficient surgical treatments of this condition. We report on a patient with an eventful course after BCS was diagnosed. After portacaval shunt surgery the patient had acute liver failure and had a successful orthotopic liver transplantation.  相似文献   
992.
Mediastinal pseudocyst is an unusual complication of pancreatitis, with only four cases previously reported in children. The extent of the pseudocyst can be defined by computed tomography or magnetic resonance imaging scan and preoperative aspiration of cyst fluid for amylase level can establish the diagnosis. Endoscopic retrograde cholangiopancreatography to define ductal anatomy can help plan the appropriate drainage procedure. Although exceedingly rare, the diagnosis of pseudocyst should be considered for any cystic mass in the abdomen or thorax, even in the absence of elevated amylase or history suggesting pancreatitis.  相似文献   
993.
994.
In this investigation is demonstrated that the nurse needs, in order to carry out a successful work, to learn about the composition of the population of the area under her care. In Patana, a Maisí municipality with 165 inhabitants, 93 male and 72 females, prevailing ninth grade school level and an initial low hygienic culture level, which is considered as regular at the present time, intestinal parasitism and malnutrition are the main diseases in the zone. It is well demonstrated that there is a wide relationship between hygienic conditions at home and community and the incidence of the fore-mentioned diseases and that the educational work performed by the nurse in the area under her care exerts a positive influence, but the support of grassroot mass organizations is required.  相似文献   
995.
Adult female rats were i.p. infused (Alzet osmotic minipumps) with neurotensin (NT, 2 micrograms/rat/day for 7 days), arginine-vasopressin (AVP, 2 micrograms/rat/day for 8 days), bombesin (BM, 0.75 microgram/rat/day for 7 days) or injected with neuropeptide Y (NPY, 0.5 microgram/rat twice a day for 4 days). NT infusion increased absolute and relative thyroid gland weight and decreased serum T4 level, while serum TSH and T3 levels remained unchanged. AVP treatment increased thyroid gland weight and serum TSH and T4 levels and a similar effect was induced by prolonged BM infusion. On the other hand, NPY administration had no effect either on thyroid gland weight or on serum TSH, T4 and T3 levels. Results of the present study thus clearly demonstrate a potent stimulatory action of AVP and BM on thyroid gland function and suggest that this effect is mediated by the pituitary gland. On the contrary, prolonged NT infusion decrease serum T4 level while NPY had no effect on thyroid gland function.  相似文献   
996.
997.
We have identified the A3243G heteroplasmic point mutation in mitochondrial DNA from a female patient with headache as the main clinical feature. The mitochondrial origin of her disease was only suspected because of her brother with MELAS syndrome. Morphological and biochemical studies failed to reveal mitochondrial respiratory chain dysfunction in her muscle which contained 65% of mutated mitochondrial DNA molecules. Molecular studies performed among four generations (in the blood of seven subjects) showed the variable transmission of mutated molecules and pointed out the difficulty in giving genetic counsel.  相似文献   
998.
Neutrophil bactericidal activity was assessed in patients with type 1 (n=45) and Type 2 diabetes mellitus (n=68) and non-diabetic control subjects (n=40) by measurement of whole blood chemiluminescence. Though chemiluminescence values tended to be highest in the non-diabetic subjects these differences were not statistically significant (mean ± SD) (2.73 ± 1.65 mV (controls), 2.33 ± 1.41 mV (Type 1 diabetes) and 2.38 ± 1.12 mV (Type 2 diabetes), F=1.12, p=0.33). Significant negative correlations were evident, however, in patients with both Type 1 and Type 2 diabetes between chemiluminescence and glycated haemoglobin (rs=-0.35, p=0.005 (Type 1), rs=-0.45, p=0.002 (Type 2), fructosamine (rs=-0.36, p=0.003 (Type 1), rs=-0.42, p=0.004 (Type 2)), and random blood glucose (rs=-0.25, p=0.04 (Type 1), rs=-0.48, p=0.001 (Type 2)). Changes in whole blood chemiluminescence in a further group of 10 patients with Type 2 diabetes mellitus commenced on insulin therapy were followed for 21 days. Serum fructosamine concentrations fell significantly over this time (524 ± 58 μmol l?1 to 405 ± 47 μmol l?1, p<0.001), however, although chemiluminescence values tended to rise these changes were not statistically significant (1.01 ± 0.38 mV to 1.60 ± 0.91 mV, S=4.24, df=5, p=0.52). These results suggest that impaired neutrophil bactericidal function is associated with poor blood glucose control. While it is likely that neutrophil bactericidal function will improve as blood glucose control improves, further studies are required both to confirm this and to demonstrate a reduction in the incidence of clinical bacterial infection.  相似文献   
999.
1000.
Cellular toxicity and cellular carcinogenesis are closely linked. In the kidney, this relationship has been emphasized by the recent discovery of a number of putatively non-mutagenic chemicals that result in acute and chronic toxicity and ultimately in carcinogenesis, especially in the male rat. Many, but not all such compounds, result in renal PTE phagolysosomal overload. At the same time, known metabolites of other carcinogens, e.g., HCBD and FBPA, result in acute renal injury and/or necrosis, followed by chronic tubular disease, interstitial nephritis, and ultimately carcinogenesis. A series of cell mechanisms have been suggested that lead from acute cell injury to altered control of cell division. These mechanisms appear to involve ion deregulation, (especially [Ca2+]i) resulting from a variety of continued injuries, (e.g., oxidative stress from inflammatory cells) and ultimately leading to altered gene expression.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号